When I compared both websites it seems that both sites offer the same features except for storage space. Google sites allow up to 10 GB of storage compared to only 2 GB on wikispaces.

Advantages of wikispaces include being a user-friendly website. I was able to create pages quickly and easily. The editing of the pages is also fairly easy and straightforward. The pages are automatically added to the sidebar (this is something I had to do manually in Google sites)

Some of the disadvantages of wikispaces is the lack of options when it comes to page layouts and color choices. Some other disadvantages are the limited font options and general formatting of individual pages. I think it would be more exciting if they could offer more options.

Regardless of these disadvantages I personally found the use of wikispaces easier and more user friendly than Google sites. I created the pages easily and quickly and it did not involve a lot of work to create them. When I used the Google site it took me a while to understand how it works and I needed to watch some of their tutorials. I didn’t have to do this in wikispaces.
What I would like on both sites is a way to organize helpful or favourite websites in a way that is easy to navigate and not in list format.

I would potentially use a wiki with my students to track their progress as language learners and also use it in specific group projects. Infact I am planning to create a wiki for every class that I'm teaching.